Ventilation Concepts

Why Ventilate?

• Enemies are HEAT and MOISTURE
• Evident in all geographical areas Year round
• HEAT
• Unventilated attics often are 140 to 150 degrees
• Damages shingles, roof sheathing, and radiates into living area
• MOISTURE
• Moisture is the #1 enemy
• Causes rot, mildew, mold, paint blisters, ineffective insulation
• HEAT and MOISTURE
• Results in "sick attics"-Toxi Mold and Mildew

Mold Facts

• Attics, crawl spaces, and basements are prime sources for excess moisture.
• Spores need a food source, heat, and moisture to begin colonizing
• Usually improper intake is the culprit in moisture related problems in attics.
• Extreme caution should be exercised if an odor or colony is detected.

Mold spores colonize on wood members which provide food source.  Wet insulation compacts and loses it's R-Value.  Imagine a pair of jeans put into the dryer and it becomes soft like insulation in your attic should be but take moisture being produced on metal objects dripping onto the insulation getting wet then drying out hard like a pair of jeans left out to air dry versus the dryer becomes brittle and hard, compact.  Moisture can then become frost in the attic.  When the frost thaws, if can literally "rain" in your attic, damaging insulation and ceiling drywall. Is it black in you attic, is the wood all moldy or blackened out then you may have a bad case of mold, moisture buildup, improper ventilation both intake and exhaust.

Other than Vent manufacturers, who says ventilation is important? Shingle Manufacturers Insulation Manufacturers Paint Manufacturers Window Manufacturers Building Codes Utility companies HVAC Companies All Promoters stress the need for Adequate or Proper Ventilation.

What is the Market for Ventilation Products? Industry Statistics-Less than 10% of existing homes are properly ventilated.  This lack of ventilation is not due to cost it is due to the lack of knowledge. Every roofing package sold should include ventilation. Ventilation shold be checked or quoted on every insulation package sold.

Keep vents the same, do NOT mix the vents and keep them on the SAME SIDE!  Air will take the path of least resistance hence a roofing contractor should avoid creating a battle between vents by mixing them and putting them on more than one side depending on the application as well because on a cottage style roof you can put them on 3 different sides but they must be close to each other.

Most builders are now installing and have been in the past regular vents at the eave for intake, this should NOT be done as weather infiltration will occur and create damage to your insulation and the rest of the attic, or regular vent goes in place of the bathroom flapper vent which creates the same problem for the home owner.  Soffits should be your only source of intake, no low installed roof vents can go it's place.

Avoid placing ridge vents on dormers when dormers are lower than the main ridge and connected to the main attic.
  The main ridge will look at the closest vent for intake air.  There is a high probability that the dormer vent will allow weather infiltration.  Seperate the attic areas using plastic sheeting or wood to create a stand alone attic. 

3 Must Do Steps
1. Install all exhaust ventilation at the same height within a comon attic area. 
Installation of exhaust vents at more than on level on a roof allows the upper exhaust to pull air in from lower exhaust vents rather than from the soffit intake vents.  Intake air must come from the soffit vent area to properly ventilate the total attic area and eliminate weather infiltration.

2. Install only one type of Exhaust Venitlation within a common attic area.
Exhaust Vents pull air fromt he easiest intake source.  The use of two or more types of exhoust vents such as Poer Vents with Roof vents or Gable Vents with Ridge VEtns or Roof Vents could make one of these vents act as intake for the other.  Intake air must come from the soffit vent area to properly ventilate the total attic area and eliminate weather infiltration.

3.  Install a balance system of Intake and exhaust Ventilation.
50% Intake Vents-Soffit Panle systems ar a common source of intake ventilation in today's homes.  Please keep in mind that it takes ten or more vented soffit panels to equal the ventilation capacity of one 16 X 8 soffit fent.  We highly recommend that you install all vented soffit panels and use air chutes in every rather/truss soffit opening.
50% Exhaust Vents-Use your Vetilation Selector Guide formula provided by your contractor and make sure they are Air Vent Certified or you will void your warranty, to determine the number of vents needed to properly ventilate an attic to meet the ventilation minimum property standard.  Roof shingle and insualtion warranties require it!